DLCO measures how efficiently gas crosses from the alveoli into the blood. Because hemoglobin is required for that transfer, a low blood count can make a normal lung look impaired unless corrected.
Fewer red cells lower measured DLCO — the correction adjusts to a normal hemoglobin.
DLCO tests the gas-exchange surface specifically, so early interstitial lung disease or pulmonary vascular disease can impair diffusion before airflow measurements change.
Hemoglobin carries the carbon monoxide across, so anemia lowers measured DLCO and can make genuinely normal lungs look impaired. Correcting to a reference hemoglobin isolates the lung's true transfer ability.
Roughly 75–140% predicted (uncorrected). It's reduced in fibrosis, emphysema, and anemia, and can be elevated in pulmonary hemorrhage, asthma, obesity, or polycythemia.
Yes — exact constants differ by reference equation and by sex/age. This tool uses the common Cotes-style adjustment to a reference hemoglobin of about 14.6 g/dL.